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  <div class="section" id="cmp0000">
<span id="policy:CMP0000"></span><h1>CMP0000<a class="headerlink" href="#cmp0000" title="Permalink to this headline">¶</a></h1>
<p>A minimum required CMake version must be specified.</p>
<p>CMake requires that projects specify the version of CMake to which
they have been written.  This policy has been put in place so users
trying to build the project may be told when they need to update their
CMake.  Specifying a version also helps the project build with CMake
versions newer than that specified.  Use the <span class="target" id="index-0-command:cmake_minimum_required"></span><a class="reference internal" href="../command/cmake_minimum_required.html#command:cmake_minimum_required" title="cmake_minimum_required"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">cmake_minimum_required()</span></code></a>
command at the top of your main <code class="docutils literal notranslate"><span class="pre">CMakeLists.txt</span></code> file:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>cmake_minimum_required(VERSION &lt;major&gt;.&lt;minor&gt;)
</pre></div>
</div>
<p>where <code class="docutils literal notranslate"><span class="pre">&lt;major&gt;.&lt;minor&gt;</span></code> is the version of CMake you want to support
(such as <code class="docutils literal notranslate"><span class="pre">3.14</span></code>).  The command will ensure that at least the given
version of CMake is running and help newer versions be compatible with
the project.  See documentation of <span class="target" id="index-1-command:cmake_minimum_required"></span><a class="reference internal" href="../command/cmake_minimum_required.html#command:cmake_minimum_required" title="cmake_minimum_required"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">cmake_minimum_required()</span></code></a> for
details.</p>
<p>Note that the command invocation must appear in the <code class="docutils literal notranslate"><span class="pre">CMakeLists.txt</span></code>
file itself; a call in an included file is not sufficient.  However,
the  <span class="target" id="index-0-command:cmake_policy"></span><a class="reference internal" href="../command/cmake_policy.html#command:cmake_policy" title="cmake_policy"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">cmake_policy()</span></code></a> command may be called to set policy <code class="docutils literal notranslate"><span class="pre">CMP0000</span></code>
to <code class="docutils literal notranslate"><span class="pre">OLD</span></code> or <code class="docutils literal notranslate"><span class="pre">NEW</span></code> behavior explicitly.  The <code class="docutils literal notranslate"><span class="pre">OLD</span></code> behavior is to
silently ignore the missing invocation.  The <code class="docutils literal notranslate"><span class="pre">NEW</span></code> behavior is to issue
an error instead of a warning.  An included file may set <code class="docutils literal notranslate"><span class="pre">CMP0000</span></code>
explicitly to affect how this policy is enforced for the main
<code class="docutils literal notranslate"><span class="pre">CMakeLists.txt</span></code> file.</p>
<p>This policy was introduced in CMake version 2.6.0.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>The <code class="docutils literal notranslate"><span class="pre">OLD</span></code> behavior of a policy is
<span class="target" id="index-0-manual:cmake-policies(7)"></span><a class="reference internal" href="../manual/cmake-policies.7.html#manual:cmake-policies(7)" title="cmake-policies(7)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">deprecated</span> <span class="pre">by</span> <span class="pre">definition</span></code></a>
and may be removed in a future version of CMake.</p>
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